Research and Teaching Interests

Simulation of Semiconductor Properties: Ourresearch in this area involves an intimate contact with experimental thrusts in various areas of semiconductor science ranging from the synthesis process to the characterization of a broad range of physical and chemical properties. The quantitative simulation of chemical vapor deposition (CVD) processes used to grow new semiconductor systems requires a highly quantitative treatment of gas-gas and gas-solid interactions. As new gas phase sources emerge they often drive synthesis/growth conditions into unconventional regimes, making the insight from simulations invaluable. We use first principles quantum chemistry methods to study the vibrational, optical and chemical properties of new molecular precursor molecules, while theoretical solid state techniques are used to study the thermoelastic and dielectric behavior of bulk and thin-film semiconductors. We also carry out large scale quantum molecular dynamics simulations to study precursor decomposition and/or deposition, hydrogen desorption clustering reactions as well as solid state phenomena such as elemental diffusion. Current research focus areas include: (i) predictive simulation of the Raman and IR spectra of metastable random semiconductor alloys, (ii) epitaxial stabilization of semiconductor heterostructures, (iii) simulation-based prediction of new wide-band gap boron based alloys and interfaces.

Carbon Sequestration: Fossil fuels currently provide 85% of the world’s energy needs, with the majority coming from coal, due to its low cost, wide availability, and high energy content. CO 2 mineral sequestration - the conversion of stationary-source CO 2 emissions into mineral carbonates - has recently emerged as one of the most promising greenhouse gas mitigation options, providing permanent CO 2 disposal, rather than storage. Magnesium-bearing feedstock minerals (serpentine or olivine) are specially processed and allowed to react with CO 2 under controlled conditions to produce a mineral carbonate (MgCO– 3) which is both environmentally benign and stable on a geological time scale. Current research focus areas include: (1) predictive first-principles simulations of complex reaction processes among the gaseous, liquid and solid reactants and products, (2) in situ synchrotron studies of CO 2 mineralization using a novel high- pressure hydrothermal micro-reactor cell, (3) large scale classical molecular dynamics simulations of non-ideal, high-concentration supercritical aqueous solutions. Other research interests also include: (1) simulation-based prediction of novel materials, (2) theory and simulation of low-temperature surface phenomena such physisorption, wetting transitions and quantum reflection, and (3) nanoscience and nanotechnology education ( http://joxer.eas.asu.edu/NUE).